The generation of Maxwell displacement current (MDC) across nematic liquid crystal (LC) cells triggered by the conformational change of surface monolayers is analyzed. It is theoretically shown that the change in the internal electric field formed in LC cells by the polarized surface monolayers and the change in the capacitance of LC cells due to the change in the orientational alignment of LCs are responsible for the generation of MDC. Eased on this theoretical analysis, we discuss MDCs across p-pentyl-p’-cyano-biphenyl LC cells induced by photoisomerization of surface azobenzene monolayers.